Map Area Calculator
What this tool measures
The area calculator measures any shape you draw on the map. Tap to drop points around a field, roof, lot, or park; once you have three or more, it reports the enclosed area and the perimeter.
Area is calculated geodesically — on Earth's curved surface, not a flat grid — and you can read it in acres, square feet, m², hectares, square miles, or km². Drag any point to fine-tune, undo the last point, or start a second area.
Want a fixed size instead of a traced shape? The acre calculator drops a true-scale acre overlay you can place anywhere, and the radius map draws distance circles.
How to measure an area
Find the spot
Search an address or pan the map
Drop points
Tap each corner of the shape
Close it
3+ points → area & perimeter show
Adjust
Drag points; Undo to step back
Export
KML or PNG; add more areas
What can you measure?
Anything you can trace from above. Each job below reads a specific number off the tool — square feet, acres, or the perimeter line — so pick the readout that answers your question.
Roof area for solar
Trace each roof plane from satellite view and read the total in ft² or m². A standard residential panel is roughly 1.7 m² (about 18 ft²), so a rough panel count is usable roof area divided by 1.7 m². Derate for shading, vents, and fire setbacks, and treat the drawn area as the ceiling, not the installed size.
Lawn: sod, seed, and fertilizer
Trace the grass and read ft² or m². Sod, seed, and fertilizer are sold by a coverage rate printed on the bag or pallet, so multiply your measured area by that rate instead of pacing the yard off by foot. Draw beds and the driveway as separate areas if you want to subtract them.
Lot and parcel size
Trace the property boundary and read it in acres, ft², or hectares. It is a fast sanity check against a listing's stated lot size, or a way to compare two lots before you pull the plat. The trace follows what you can see — fences, hedges, pavement — which may not match the legal parcel (see below).
Fence line — use the perimeter readout
For fencing you do not want the area, you want the perimeter. Trace the run and read the perimeter figure the tool shows next to the area: that is your linear feet or metres of fence, minus gate openings. The same number gives a retaining-wall run, bed edging, or the lap distance around a track.
Garden, field, or paddock
Trace a raised bed, a paddock, or an irregular field and read m²/ft² for planting and compost math, or acres/hectares for grazing and yield. Drop extra points along the curves — the geodesic area handles any shape, not just rectangles.
Measure square footage from a map
To get square footage, trace the outline and set the unit to ft². The readout updates as you drop each point, and switching to m², acres, or hectares afterward changes only the number, never the shape you drew. It is the fastest way to size a roof, patio, parking lot, or building footprint from above without a tape measure.
Two tips for a tight number: zoom in before placing points, since each point lands exactly where you tap; and remember satellite view shows the building footprint, not interior rooms — for indoor floor area you would trace the outer walls, then adjust for wall thickness.
Area unit reference
| Unit | Equals |
|---|---|
| 1 acre | 43,560 sq ft · 4,046.86 m² · 0.4047 hectares |
| 1 hectare | 10,000 m² · 2.471 acres · 107,639 sq ft |
| 1 square mile | 640 acres · 2.59 km² · 27,878,400 sq ft |
| 1 km² | 100 hectares · 247.1 acres · 0.3861 sq mi |
Conversions are exact/standard; the tool carries full precision internally and rounds only for display.
Why geodesic, not flat, area
Treating latitude and longitude as flat x/y coordinates overstates area, because a degree of longitude shrinks as you move toward the poles. This tool instead computes the geodesic area on a spherical Earth model, so a shape measures the same whether it sits near the equator or far north.
Perimeter uses the Haversine (great-circle) distance between consecutive points. For everyday parcels the spherical model is accurate to well under a percent; survey-grade work uses an ellipsoidal model, which is beyond what a quick map measurement needs.
Why your measurement may differ from official records
A map trace is an estimate, not a survey. Two things make it read differently from a county assessor, deed, or land-registry figure:
Drawn outline vs. legal parcel
You trace what is visible from above — fences, hedges, pavement — which often does not match the surveyed legal boundary. Fences get built off the line, easements and setbacks are invisible from the sky, and old boundaries drift. The recorded parcel comes from a licensed survey and the official plat; treat a trace as a picture of it, not a replacement.
Spherical model and imagery offset
This tool models Earth as a sphere; professional GIS typically uses an ellipsoid (WGS 84) and a local projected coordinate system, a difference well under a percent on a normal lot. Satellite imagery can also sit slightly off true ground position, and your point placement adds a little more. For anything legal — a sale, permit, or dispute — use the recorded survey.
Can I calculate area on Google Maps?
Yes — on the Google Maps website. Right-click a spot, choose Measure distance, click around the shape, and click your first point again to close it; the panel at the bottom shows the distance and the enclosed area. For a one-off check, that is often all you need.
Two limits are worth knowing. The Google Maps mobile app does not offer closed-shape area (as of 2026) — you need a desktop browser, or Google Earth, which shows area and perimeter in its side panel. And the measure tool is built for a quick look, not for keeping work: there is no way to save the outline, hold several labelled areas with a running total, switch the same shape between acres, hectares, ft², m², sq mi, and km², or export it as a KML or PNG file.
That is the gap this tool fills. It runs on your phone as well as desktop, keeps every area you draw with its own colour and a running total, flips between all six units on tap, and exports KML (for Google Earth, QGIS, or a CRM) or a PNG snapshot. Use Google Maps for a five-second check; use this when the measurement has to travel. See Google's Measure distance help page for their current steps.